Cytogenetic characterization of Metynnis maculatus (Teleostei; Characiformes): the description in Serrasalminae of a small B chromosome bearing inactive NOR-like sequences
Contribuinte(s) |
UNIVERSIDADE DE SÃO PAULO |
---|---|
Data(s) |
20/10/2012
20/10/2012
2009
|
Resumo |
Mitotic chromosomes of Metynnis maculatus (KNER 1860) (Teleostei, Characiformes), a fish species that occurs in the Amazon and Parana-Paraguay river basins, were analyzed for the first time by Giemsa and Ag-NOR staining, C-banding and fluorescence in situ hybridization (FISH) with 18S and 5S rDNA sequences. The basic chromosome number of the species is 2n=62 (32M+22SM+4ST+4A) and, in addition to the 62 regular chromosomes, one small acrocentric supernumerary B chromosome was found in part of the specimens analyzed. Four active NORs were present, and constitutive heterochromatin blocks were found in the pericentromeric region of several chromosomes. A heterochromatic block was also present in the interstitial portion of the submetacentric NOR-bearing pair and the B chromosome was entirely heterochromatic. FISH using an 18S rDNA probe confirmed the results obtained with AgNO(3) staining, and an additional signal was also present on the B chromosomes. 5S rDNA sequences mapped only to the largest acrocentric pair. This is the first description of supernumerary B chromosomes in Serrasalminae, and this karyotype characterization may be useful in further studies about chromosome evolution in this fish group. Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Brazilian agencies Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) Conselho Nacional do Desenvolvimento Cientifico e Tecnologico (CNPq) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) |
Identificador |
CARYOLOGIA, v.62, n.2, p.95-101, 2009 0008-7114 |
Idioma(s) |
eng |
Publicador |
UNIV FLORENCE BOTANY INST |
Relação |
Caryologia |
Direitos |
restrictedAccess Copyright UNIV FLORENCE BOTANY INST |
Palavras-Chave | #B chromosome #Characidae #Cytogenetics #rDNA #Serrasalminae #NUCLEOLUS ORGANIZER REGIONS #FISH ASTYANAX-SCABRIPINNIS #SUPERNUMERARY CHROMOSOMES #RIBOSOMAL CISTRONS #CHARACIDAE #PISCES #EVOLUTION #FREQUENCY #RODENTIA #ORIGIN #Genetics & Heredity |
Tipo |
article original article publishedVersion |